There's no way to battle in gyms — the places on your map with the massive Pokémon hovering over them, that look like some sort of futuristic cone — without getting to level five. So, how's best to get there quickly?
Some quick tips:
-Tap on every PokéStop you can. When they're blue, they have items in them, and you get a little bit of experience, which helps out a ton in the early goings. You can return to Pokéstops over and over, and they flip over pretty quickly (about five minutes as far as we can tell).
-As you walk around, you may feel your phone vibrate. That means a Pokémon is near! Tap it, swipe to throw a Poké Ball at it, and it's yours. You'll get a lot of experience for doing this, so do it as often as possible.
-If you feel like spending money, you can use it to buy Lucky Eggs from the in-game store. A Lucky Egg will double the amount of experience you get for 30 minutes, so if you have one, use it before you start doing all of the above.